The Atari ST computers were a series of home computers made by Atari Corporation between the mid 1980s and early 1990s. These machines competed most directly with the Amiga by Commodore for the home user market. The ST was a popular machine amongst musicians because of its built-in MIDI ports. It also had some superb desktop publishing capabilities that beat all of the competition at the time.

The vast majority of popular entertainment software releases from about 1985 -1992 were converted to the Atari ST platform, so the system has a huge software library behind it. The ST wasn't just games though, as Word Processors, Spreadsheets, publishing, MIDI, and other applications were available.

The ST died at the hands of the immense growth of the PC and Mac platforms. Atari's poor marketing certainly didn't help.

"Faster and with better graphics capabilities than an IBM AT, it could be a great vehicle for low cost networks, desktop publishing, and visual database management software."

-- Microtimes

Atari as we knew it is gone. In 1996, Atari was merged into JTS Corp. (a hard disk manufacturer) who promptly shut the company down. The rights to all of Atari's products were then sold to Hasbro Interactive. Hasbro converted a number of Atari's classic games for use on the PC's, and several gaming consoles.

In early 2001, Hasbro Interactive was sold to Infogrames, a French software publisher. Although Infogrames has expressed interest in reviving the Atari name & software library, It is doubtful that they will ever make a serious push to resurrect the technologies used in the ST, or any of Atari's other gaming/computing products. Several companies are making Atari clones based on the TOS operating system, but they are mainly available in Europe.

The ST was made available shortly after Jack Tramiel acquired Atari from Warner Communications in 1984. Jack left Commodore after several disputes with a number of stockholders, who wanted to see new management in the company. Jack and his family bought Atari with the intent of hurting Commodore. The arcade games division of Atari, and AtariTel remained part of Warner.

1984 was brutal year for Atari. Jack Tramiel started hacking up the company. Atari had over 6,000 employees during it's heyday. Jack reportedly cut the company headcount down under 500. Several lawsuits were filed against Atari for not paying it's bills. Atari consolidated the 40 buildings that it occupied in California down to 7. More reductions are made worldwide.

In January 1985, Atari announced the ST series of computers. Atari promoted the system as "Powerful as a MacIntosh for half the price." US News and World Report called the new system "a quantum leap in computer value."

Later that year, the first-ever CD-ROM unit for any computer was displayed by Atari.

"The ST is an amazing bargain, much more of a computer 'for the rest of us' than the Mac ever was."

-- Byte Magazine

There were three main models the ST computer. These were ST, the STFM and the STe. Each of these came in two varieties. The 520 model featured 512Kb RAM, and the 1040 with 1Mb RAM. Most ST systems feature a 3 1/2 inch 720kb floppy drive, although the early 520ST machines came with a single-sided 3 1/2 inch 360kb drive.

The ST, STFM and STe have slightly different capabilities. All home-user ST units support three video modes; 320x200, 16-color, 640x200, 4-color and 640x400 monochrome.

The original ST and STFM have a palette of 512 colors (three bits each for red, green and blue level). The STe supports a 4096 color palette, the same as the Amiga. On the ST and STFM, a Blitter (simple graphics coprocessor) is an optional extra; on the STe, it is standard.

The STe also has easy-to-expand 30-pin SIMM sockets for up to 4Mb of internal RAM, and much more advanced sound capabilities. The original ST and STFM use the General Instruments AY-3-8910 (related to the Yamaha YM2203) three-channel tone generator, a very primitive audio output device which was also used in several 8-bit platforms. The STe has stereo DMA 8-bit PCM audio, very similar to the Amiga's 4-channel DMA sound system.

The Atari's operating system is called TOS, which stands for "Tramiel Operating System." On all but the very early Atari ST's, TOS was built into ROM. There are four main components to TOS:

VDI - The VDI, or Virtual Device Interface, provides most of the output routines (such as printing) and the mouse input routines. VDI handles drawing lines, circles, boxes, and so on, and also clipping and block image copying. The VDI has an optional, extension called GDOS, which is responsible for font management. (Many programs require that this extension be loaded.) Later GDOS versions support Bitstream and True Type fonts. VDI was developed by Digital Research (DRI).

AES - The AES, or Application Environment Service, is built on top of the VDI and GEMDOS. AES was developed by Digital Research (DRI). It provides high-level routines for drawing and managing elements on the screen, including windows and mouse input. Most of the GEM routines called by an active application are handled by the AES.

Note: VDI and AES are collectively known as GEM, or Graphical Environment Manager. GEM Desktop is the basis for all the visual elements of the Atari screen. GEM Desktop is the application program directly responsible for user interaction with TOS.

GEMDOS - GEM Disk Operating System, or GEMDOS, is a set of character-based file and device input/output routines used by GEM. It is based on the machine-specific GEM BIOS (Basic Input Ouput System) routines. Also available is the Atari XBIOS, which provides additional machine-dependent operations not used by GEMDOS.

BIOS - The BIOS (Basic Input/Output System) provides many hardware related functions and is essentially compatible with the BIOS used in the PC's of today. The ST BIOS also contains an additional element called XBIOS, or Extended BIOS. The XBIOS functions are strictly Atari specific, and are not compatible with any other computer, except Atari ST systems.